1. Field of the Invention
The invention relates to an arrangement for permitting the transmission of an electrical signal between areas of different pressure.
2. Background Art
A need arises in many applications for transmitting an electrical signal between areas of different pressure. In a tank that contains a fluid under pressure, for example, it is often necessary to conduct such a signal into the tank to control a solenoid-operated valve disposed inside the tank. Because the tank must be breached in order to pass a wire through to the valve, some provision must be made for maintaining a seal so as to prevent leakage of contents out of the tank, or to prevent contaminants from passing into the tank.
Various structures are known for establishing such a seal. U.S. Pat. No. 3,352,963, for instance, discloses a fitting including a high pressure side conductor rod and a low pressure side conductor rod that are joined together by a connector, which is received in an insulating sleeve. The sleeve and the connector are disposed within a pair of nested metal sleeves having complementary tapered sealing surfaces and seats. A hollow loading nut houses the sleeves and connector, and draws them together into sealing relation when the nut is threadably secured to a vessel wall. While this fitting is adequate for transmitting an electrical signal between areas of different pressure, the fitting is complex, bulky and costly to produce.
The invention addresses the shortcomings of the prior art by providing an arrangement for passing an electrical signal between different areas that is simple, compact and inexpensive.
Under the invention, an arrangement for passing an electrical signal between first and second areas includes a body disposable between the first and second areas and having an aperture. A first sleeve is at least partially disposed in the aperture and defines a first opening. A second sleeve is also at least partially disposed in the aperture and defines a second opening. The arrangement further includes an electrically conductive element having a first portion disposed in the first opening, and a second portion disposed in the second opening.
Preferably, each sleeve is non-threadingly engaged with the body. As a result, the sleeves can be provided with a simple, low cost configuration.
The electrically conductive element may be a terminal having a radially extending projection disposed between the first and second portions. The arrangement also preferably includes a seal disposed between the sleeves and engaged with the body and the projection.
The arrangement also preferably includes a first conductive member in electrical communication with the first portion and adapted to extend into the first area, and a second conductive member in electrical communication with the second portion and adapted to extend into the second area.
Further under the invention, an arrangement is provided for passing an electrical signal between a first area having a first pressure and a second area having a second pressure, wherein the first pressure is normally greater than the second pressure, thereby creating a pressure differential. The arrangement includes a body disposable between the first and second areas and defining a passage having a shoulder. A first sleeve is non-threadingly engaged with the body and at least partially disposed in the passage. The first sleeve also defines a first terminal opening. A second sleeve is non-threadingly engaged with the body and disposed in the passage between the first sleeve and the shoulder. Furthermore, the second sleeve defines a second terminal opening. The arrangement also includes a terminal having a radially extending projection and first and second shank sections extending from the projection. The first shank section is disposed in the first terminal opening, and the second shank section is disposed in the second terminal opening. When the terminal is exposed to the pressure differential, the projection is urged toward the second sleeve, thereby urging the second sleeve toward the shoulder.
These and other objects, features and advantages of the invention are readily apparent from the following detailed description of the best modes for carrying out the invention, when taken in conjunction with the accompanying drawings.